The discriminability and pitch of two-component complex tones appears to depend upon an envelop-weighted average of their instantaneous frequency fluctuations. This study extends previous work from this laboratory. Three lines of research are to be followed. Concomitant changes in complex tone discrimination and pure tone frequency dL's with changes in signal duration or presentation level should support a common processing mechanism. Evidence from previous work suggests that the linear evelop weighting function should b modified. Studies using the two component complex tones as maskers should indicate the necessary modifications. The third line of research will address the pitch evoked by vowel-like sounds. We have just begun the study of the pitch of synthetic vowels.